The network-resources needed to deliver a service are constrained by the interconnecting technologies that make up the network. Due to business reasons, the capacity of the service provider's network cannot grow linearly with the addition of new end users. As a result, the service provider must perform what is referred to as oversubscription. This means the same resources in the network are sold multiple times to different end users.
Oversubscription is based on the principle that not all users will be consuming their data pipe simultaneously. The service provider estimates how much simultaneous usage there will be of the network and provides some maximum limits to the amount of resources used by each data pipe. During times of congestion (i.e., many end users trying to access the network at the same time with traffic levels exceeding what the network can handle) the quality of service associated with the sessions may degrade substantially because the network cannot differentiate between those sessions that require special treatment and others that do not require such special treatment. This results in the resources consumed by a service (or an aggregate of services) being limited by the characteristics of the data pipe to the end user.
For example, in a video-on-demand application (e.g., where a user requests a video clip or movie) if an end user wishes to download streaming video from a content provider (i.e., a dynamic service) via today's static data pipe the viewing experience would likely be much poorer than the viewing experience one would get by watching traditional broadcast TV. The reason for this is that there is a certain amount of bandwidth that is needed for the video frames to be delivered which if not made available by the network, results in poor viewing quality (e.g. jerky, frame loss, etc.) for the user. Currently, a service provider access network is based on best effort delivery of content, which can be inadequate compared to the quality of service needed for such service delivery. This is especially true in a shared contention based access network where multiple users contend for the same set of network resources.
One of the issues plaguing service providers today is the existence of bandwidth hogs. The phrase bandwidth hogs refers to the typically smaller percentage of users/end points which use up a majority of the delivery network resources. Today, there is no easy or graceful means by which the service provider can control the access for those bandwidth hogs because of the static nature of the data pipes. A bandwidth hog can consume as much bandwidth as allowed by the data pipe, for as long as the end point wants to, and the sessions associated with bandwidth hogs compete for the same resources needed by other non-bandwidth hog related sessions.
The properties of the static data pipe are such that there may be some minimum and maximum bandwidth made available for the subscriber or end user. Currently, once provisioned, this availability of bandwidth cannot be changed without re-provisioning. Thus static provisioning results in the inefficient utilization of network resources. Provisioning is the act of statically configuring the service profile of the subscriber or end user in either some customer premise equipment and or any intermediate network elements participating in the delivery of the service. In the case of the customer premise equipment (cable modem), a rebooting of the device is necessary in order to be provisioned. The service provider has a limited set of resources in its network, and thus has to ensure that the resources available in its network can satisfy the needs of the end users that it has agreed to take on as customers. The end user uses the data pipe to receive content from another location in either the service provider's network, or beyond. The end user can also use the data pipe to send content from the local (in home or business) site to the remote end, which can either be another content provider or a peer (e.g. another end user in the service provider's network) or any other legitimate entity that can receive such content. Regardless of the type of content the end user wishes to transfer over the data pipe, be it for an on-demand streaming video application, or a telephony application, or Instant Messaging application (with or without the video component), or just Internet browsing, the data traffic associated with the dynamic service is constrained by the resources that were statically provisioned for the end user.
Today, the model for offering differentiated services to the end user is Tiered Services (e.g., bronze, silver, gold). Service providers offer a tiered service model in which the characteristics of the data pipe may differ based on the tier that the end user or subscriber has subscribed to. Tiered services do not address the needs of dynamic services because the tier to customer association is static, and the tier and its associated characteristics are also static.